Seasonal abundance of equine strongyles (Nematoda: Strongylidae) in the State of Rio de Janeiro, Brazil

I.V.F Martins,L Grisi,M.J.S Pereira,F.B Scott

doi:10.1590/s0102-09352005000100006

Abstract

The seasonal abundance of lumenal and larval forms of equine strongyles in the State of Rio de Janeiro, Brazil was evaluated. Thirty horses referred to the Federal Rural University of Rio de Janeiro were necropsied and their gastrointestinal tracts were separated into stomach, small intestine, cecum, ventral colon, dorsal colon and rectum. Two aliquots of 5% of the content were collected and examined for the presence of small strongyles and the rest of the content was examined for the presence of large strongyles. The mesenteric artery, liver, pancreas and peritoneum were examined for the presence of strongyle larvae. The mucosa of intestine segments was cut into parts of equal length, and each one was examined by the mural transillumination technique. Higher abundances of larvae of Strongylus equinus (P<0.10) and of adults Strongylus vulgaris (P<0.05) were observed during the dry season. Encysted cyathostome larvae had the highest abundance during the rainy season (P<0.02).

Highlights

Infections caused by strongyles constitute a severe impediment to successful horse management due to debility and death of animals, when heavy burdens are involved
The disease has been masked by severe effects of large strongyles, especially S. vulgaris, which are uncommon due to effective control programs (Lyons et al, 2000)
S. equinus larvae and S. vulgaris adults were found with higher mean abundance during the dry season than that in the rainy season

Summary

Introduction

Infections caused by strongyles constitute a severe impediment to successful horse management due to debility and death of animals, when heavy burdens are involved. The disease has been masked by severe effects of large strongyles, especially S. vulgaris, which are uncommon due to effective control programs (Lyons et al, 2000). Healthy horses can carry large burdens of adult worms of cyathostomes with no prejudicial effects, infections with these worms, at their larval stages, have increased as an important horse disease (Mair, 1994). Larval cyathostomiasis is related to the emergence of larvae from the mucosa or submucosa causing severe damage to the large intestine resulting diarrhea, colic, weight loss, ventral abdominal edema and even death (Lyons et al, 2000; Mair et al, 2000)

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